Multiple minima problem conformational energy

One of the ways of circumventing the problem of finding multiple energy minima of complex molecules is to turn to more sophisticated techniques that are capable of sampling phase space efficiently without the need to home in on particular minimum energy conformations. The two most useful techniques are molecular dynamics (MD) and the Monte Carlo (MC) method. Both approaches make use of the same types of potential functions used in molecular mechanics, but are designed to sample conformation space such that a Boltzmann distribution of states is generated. MC and MD techniques for molecular systems have been widely reviewed [11-14], and only the basics of the two methods are described below. 

The problem of finding the conformation of lowest energy is rather simple for a terminally blocked amino acid (such as a glycyl or alanyl residue) since it is a problem including only two variables (, 0) however, the location of the minimum becomes more difficult to determine even for a terminally blocked amino acid when rotations x are also included. A fortiori, when the molecule contains more than one amino acid, difficulties in finding the deepest minimum arise. As previously discussed (Section 4.1.1), the multidimensional energy surface has multiple minima. Since there is no procedure... 

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